Use history tab 

The History Tab offers a convenient way to talk to people you have talked with in the past.
Recently used talk rooms are shown at the bottom of the Home Screen.
To start a conversation with the same people, you can select a room from the History Tab to immediately start a conversation.
Select "View all" to display a list of 10 recently joined rooms.

Use your favourite room

Selecting "View all" on the Home Screen will display your conversation history.
At this point, switch tabs at the top of the screen to show a list of Favorites.
You can select a talk room to resume a conversation.
(Account registration is required to use the Favorites feature.)